Fe/Mn Bimetallic Synergistic Regulation of the Electronic Structure and Active Site Density in NiFeMn/LDH Enables Highly Efficient Oxygen Evolution Reaction

Electrolytic water splitting for hydrogen production is a key technology in the wind‐solar‐hydrogen clean energy system, and tunable hydroxide electrodes are a crucial approach to improving the oxygen evolution reaction (OER) in alkaline electrolyte. Although traditional binary LDHs have tunable compositions, they are still limited by their monotonous electronic structure and high mass transfer resistance. In this work, a NiFeMn layered double hydroxide (LDH) electrode was prepared on nickel foam by electrodeposition followed by thermal treatment and compared with NiFe and NiMn electrodes. Electron microscopy reveals a flower‐like assembly of nanosheets for the ternary material, in contrast to the more aggregated morphology of the binary controls. Electrochemical testing reveals that NiFeMn/LDH exhibits an overpotential of only 228 mV at a current density of 10 mA cm −2 , with a Tafel slope of 86 mV dec −1 . After 100 000 s of stability testing, the activity retention rate reaches 95%. Under a unified experimental framework, this study conducted a comparative evaluation of the characteristics of the prepared electrodes in terms of composition, nanosheet assembly, and OER response, providing a theoretical basis for the development of highly efficient and stable industrial‐scale OER catalysts.